For example when I start GTA IV the PSU starts making a loud noise and after 15 min the game freezes.Not only GTA IV but Crysis,Metro 2033,Need for Speed Shift...

All temperatures are normal except the motherboard. It was stable until I bought the new CPU. The old one was AMD 4000+ 2.1Ghz CPU:30 to 40 degrees on standby when playing maximum 60Video Card:45 degrees on standby and up to 65 while playingMotherboard: 45 degrees on standby and up to 67 when playing
All help would be appreciated